1. Field of the Invention
This invention relates to hydrogels, and, more particularly, to polymeric hydrogels which are crosslinked polymeric esters or amides/imides, or both, of a polymeric anhydride or acid, or copolymers thereof, which are very swellable in water, and form thin, tacky layers on a substrate, and bioadhesive products thereof.
2. Description of the Prior Art
Hydrogels are polymeric materials which can swell appreciably in water. However, what is described as hydrogels can be viscous polymeric solutions without the swelling characteristic of a true hydrogel. Such hydrogels also are not tacky, a necessary property for making bioadhesive products. See U.S. Pat. Nos. 4,740,365; 4,990,551; 5,135,753; 5,336,501; and 5,846,214. Accordingly, it is desired to provide new and useful polymeric hydrogels having exceptional swelling properties in water, and which are tacky; and bioadhesive products of such hydrogels.